1. Best make and model for the money is a broad question for which you will probably get many answers. Read this thread for some discussion.
2. Don't know about moving it around. Most transducer cables are not long enough I don't think, and I haven't heard of any extra long cable options. Perhaps there is a transducer extension that I am not aware of? Some guys mount the console unit on a Ram mount so it can easily be turned around to be seen from the bow. All that said, I personally want to know exactly how deep I am exactly underneath me while at the bow. There often can be a lot of depth difference b/t bow and stern.
3. I have had a skimmer type transducer on my TM for a long time with no problems. The skimmer type can kick up in the mount if it hits something and maybe that is why I haven't had any breaking issues? I have read of some folks mounting shoot through hull transducers in aluminum boats with good success, though I haven't tried it personally. With a shoot through, you still have to mount a temp probe on the outside if you want temp readings on the locator. Again, I have had a skimmer type on my current boat since 2005 with no issues. It reads while at speed on pad and hasn't broken off yet (knock on a wood stump).
Just my $0.01 (inflation)....
By the way, I have an aluminum Xpress boat probably similar to yours.
"We're all very different people. We're not Watusi, we're not Spartans, we're Americans. With a capital "A", huh? And you know what that means? Do you? That means that our forefathers were kicked out of every decent country in the world."
John Winger